The present invention relates to a dustproof ring and, more particularly, to a dustproof ring for preventing dust from entering a head of a ratchet wrench.
A type of ratchet wrench includes a head and a handle interconnected to the head. The head includes a first, open side and a second side having an end wall with a hole rotatably receiving a stub formed on an end face of a drive member received in a compartment defined between the first and second sides of the head. A cover plate is mounted to the first side of the head to enclose the compartment. A drive column extends beyond the cover plate for driving a socket or the like. A pawl is received in a pawl groove defined in a periphery defining the compartment. A switch is received in a switch groove in the head and engages with the pawl, so that the driving direction f the ratchet wrench can be changed by rotational movement of the switch between two positions. To prevent dust from entering the compartment of the head via the hole, an O-ring is mounted in an annular groove formed in an inner face of the end wall and in direct communication with the hole. A C-clip is mounted and imparts a force to an outer side of the cover plate, so that the end face of the drive member tightly compress the O-ring with upper and lower edges of the O-ring tightly sandwiched between the end face of the drive member and a bottom wall of the annular groove. An example of such a ratchet wrench is disclosed in U.S. Pat. No. 7,311,019. However, significant force is required to overcome the friction between the end face of the drive member and the lower edge of the O-ring and between the bottom wall of the annular groove and the upper edge of the O-ring, risking injury to the hand of a user.
Thus, a need exists for a novel dustproof ring capable of preventing dust from entering the ratchet wrench while allowing easy, smooth operation of the ratchet wrench.